In the prior art, there are several cutting devices for harvester machines. Basically, a cutting device consists of two cutting blades overlapping each other, each of which comprises several knife sections secured to a long knife bar. Once the upper knife bar (and consequently the upper knife sections) moves to the right, the lower bar moves to the left, and due to the overlapping relationship between the knife sections a shearing effect is thus created. Because this cutting device is installed on the front part of a harvester machine, the shearing effect cuts cereal and forage plants to be harvested. Though harvester machines are the objects of several improvements relating to cutting device drive mechanisms, blade design, and others, an improved cutting device for reducing crop loss during the harvest process is still a market need.
There are several patents teaching the design and function of cutting blades arrangements, driving mechanisms, blade designs, etc. For instance U.S. Pat. No. 1,017,863 of Fulton; U.S. Pat. No. 1,182,899 of Enders; U.S. Pat. No. 1,424,617 of Cambell et al.; U.S. Pat. No. 1,635,050 of McKellar; U.S. Pat. No. 1,644,962 of Swickard, U.S. Pat. No. 2,528,659 of Krause and U.S. Pat. No. 4,909,025 of Reissig et al. are examples thereof. These patents are cited only as a reference. Even when the inventions described in these documents involve improvements on cutting devices, a significant decreasing in crop loss is not achieved with any of them. This loss is created due to the defective plant stems cutting. That is, not all plant stems are well cut when the harvester machine harvests crops. Therefore the crop is not properly harvested and a significant loss is then created.
Ernest O. Hutsell describes in U.S. Pat. No. 1,647,867 a lawn mower comprising a cutting device which includes the combination of a frame, two knife bars reciprocally mounted transversely of a frame, two rods mounted above and parallel to the respective knife bars, guides in which the rods are reciprocal, and means for reciprocating the moving knife bars. Even though the mechanisms involved are useful for a lawn mower, the hard work usually involved in crop harvesting makes the become said mechanism not useful for this task. One object of the present invention resides on a new and improved cutting device for harvester machines comprising a combination of two moving cutting blades set overlapping each other, and a fixed counterblade. The shearing effect, explained above, is created between each set of moving cutting blades and the fixed counterblade. This arrangement allows an improved shearing effect by which crop loss is thus avoided.
Another object of the present invention resides in an improved harvester machine including a cutting device through which all plant stems are cut and thus crop loss is avoided.